Helium circulation refrigeration based nitrogen fixation protection type high temperature superconducting magnet
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- ZIYANG COMMERCIAL SPACE LAUNCH TECHNOLOGY RESEARCH INSTITUTE
- Filing Date
- 2025-06-27
- Publication Date
- 2026-06-19
Smart Images
Figure CN224384010U_ABST
Abstract
Description
Technical Field
[0001] This application pertains to the fields of superconducting engineering and magnetic levitation transportation, and particularly relates to a nitrogen-protected high-strength high-temperature superconducting magnet based on helium gas circulation cooling. Background Technology
[0002] Superconducting magnets can provide stable magnetic fields, which, when applied to magnetic levitation transportation, can significantly reduce drag during vehicle movement, thereby substantially increasing the upper speed limit. This represents a crucial development direction in the current transportation sector. The core component of a superconducting magnet is the superconducting coil. To achieve superconductivity, the coil typically needs to be cooled to extremely low temperatures. Based on the main material of the superconducting coil, two technical routes exist: low-temperature superconductivity (operating temperature approximately 4K) and high-temperature superconductivity (operating temperature typically 20K~50K). Due to the cooling requirements of the superconducting coil, the superconducting magnet needs a suitable cooling system. However, since the operating speed of a magnetic levitation transportation system is largely limited by the weight of the maglev vehicle, simplifying and lightweighting the superconducting magnet's cooling system, and even achieving offline cooling, is a significant technical challenge in the field of superconducting magnetic levitation transportation.
[0003] Currently, superconducting magnets used in magnetic levitation transportation can be classified into the following categories based on their cooling methods: liquid helium immersion cryogenic superconducting magnets, conductive-cooled cryogenic superconducting magnets, conductive-cooled high-temperature superconducting magnets, and nitrogen-protected high-temperature superconducting magnets. Liquid helium immersion cryogenic superconducting magnets maintain a stable temperature of 4.2K for extended periods by immersing the superconducting coil in liquid helium. Conductive-cooled cryogenic and high-temperature superconducting magnets use a cryogenic refrigerator to provide cooling, which is then conducted from the refrigerator's cold head to the high-temperature or low-temperature superconducting coil via a copper conductive structure. Nitrogen-protected high-temperature superconducting magnets immerse the high-temperature superconducting coil in liquid nitrogen, then use an external cold source to cool the liquid nitrogen, causing it to solidify and allowing the high-temperature superconducting coil to operate in a cryogenic nitrogen-protected environment.
[0004] Low-temperature superconducting magnets operate within a very narrow temperature range, typically losing quench at temperatures exceeding 6-7K. Therefore, when operating such magnets, the superconducting coils must be constantly immersed in liquid helium. Liquid helium, however, is a low-density liquid with low latent heat of vaporization, making it highly susceptible to vaporization and loss upon heating. To ensure the maglev vehicle can operate independently of the ground-based cooling system for extended periods, a complete helium reliquefaction circulation system must be installed on the vehicle. This system typically includes a refrigerator, a compression-throttling cycle, and a liquid helium storage tank. The system is highly complex, large, and heavy, placing an additional burden on the maglev system. For conductive superconducting magnets, both low-temperature and high-temperature magnets share a common drawback: the lack of a cooling medium for heat storage. If the refrigerator stops, the temperature of the superconducting coil rises rapidly, causing quench loss. Therefore, conductive superconducting magnets must be equipped with a cooling system on the maglev vehicle, typically including a cold head, a compressor, and a water-cooled compressor, again adding extra weight to the maglev vehicle. Compared to the previous three types of magnets, nitrogen-fixed protected high-temperature superconducting magnets have advantages in terms of offline cooling. Firstly, high-temperature superconducting magnets have a wider operating temperature range, which allows the superconducting coil to rise to a certain extent. Secondly, nitrogen-fixing media are very inexpensive and have good cold storage performance, allowing the superconducting magnet to be removed from the ground cooling system for a relatively long period of time.
[0005] Most of the nitrogen-protected high-temperature superconducting magnets reported in the literature currently use a refrigerator as the cold source for nitrogen fixation. This method requires mounting the refrigerator cold head on the superconducting magnet, which increases the weight of the superconducting magnet. At the same time, since the refrigerator cold head needs to conduct the cooling energy to the nitrogen-fixing cavity through a copper heat-conducting structure, the cooling rate is relatively slow. Moreover, since the cold screen inside the magnet is cooled by the refrigerator, once the refrigerator stops, the metal cold head will become a good conductor of heat, causing the temperature of the cold screen to rise rapidly, resulting in increased radiative heat leakage from the nitrogen-fixing cavity and shortening the effective time of nitrogen fixation protection. Furthermore, the nitrogen-protected high-temperature superconducting magnets reported in the literature currently employ an independent coil box structure, and the nitrogen-fixing cavity pipeline is directly connected to the external liquid nitrogen supply pipeline. During the cooling and solidification process of liquid nitrogen, because the density of fixed nitrogen is lower than that of liquid nitrogen, its volume shrinks, creating voids in the nitrogen-fixing cavity, and the thermal detachment effect of the fixed nitrogen layer leads to poor thermal contact between the fixed nitrogen and the coil box, reducing the cooling efficiency of nitrogen-fixing protection. In order to reduce the voids in the nitrogen-fixing cavity, liquid nitrogen needs to be added to the nitrogen-fixing cavity. However, because the volume of fixed nitrogen shrinks, a negative pressure is generated in the nitrogen-fixing cavity. Once it comes into contact with the external environment, air will be drawn back into the nitrogen-fixing cavity pipeline, and the water vapor in the air will freeze in the low-temperature environment, which can easily cause pipeline blockage. Utility Model Content
[0006] The purpose of this application is to overcome the problems of the prior art by disclosing a nitrogen-protected high-temperature superconducting magnet based on helium cycle cooling. The structural design of this high-temperature superconducting magnet solves the problem of offline cooling when superconducting magnets are applied in the field of magnetic levitation. At the same time, it improves the structural strength of the superconducting magnet and optimizes the temperature distribution of the superconducting coil, making it more suitable for high-speed dynamic magnetic levitation operation.
[0007] The objective of this application is achieved through the following technical solution:
[0008] A nitrogen-protected high-temperature superconducting magnet based on helium cycle cooling, the high-temperature superconducting magnet comprising: an outer Dewar, a cold screen and a nitrogen-fixing cavity, wherein the nitrogen-fixing cavity is disposed within the cavity formed by the outer Dewar, and the cold screen is disposed within the vacuum layer between the nitrogen-fixing cavity and the outer Dewar;
[0009] The nitrogen fixation chamber is composed of a nitrogen fixation chamber frame and coil plates located on both sides of the nitrogen fixation chamber frame. A coil box is provided inside the nitrogen fixation chamber, and a superconducting coil is provided inside the coil box.
[0010] The outer Dewar is provided with a cold screen pipeline for providing a cooling medium to the cold screen; the outer Dewar is also provided with a helium pipeline and a nitrogen-fixing chamber pipeline. The helium pipeline is connected to the cooling pipeline on the inner side of the coil plate for providing cooling helium to the nitrogen-fixing chamber, and the nitrogen-fixing chamber pipeline is connected to the nitrogen-fixing chamber for filling the nitrogen-fixing chamber with liquid nitrogen.
[0011] According to a preferred embodiment, the top of the cold screen is provided with a liquid nitrogen box, which is connected to the cold screen pipeline to receive liquid nitrogen; the liquid nitrogen box conducts the cooling energy generated by the vaporization of liquid nitrogen to the cold screen, thereby cooling the cold screen.
[0012] According to a preferred embodiment, a current lead is fixed to the surface of the liquid nitrogen box, the current lead being used to provide a power supply circuit for the excitation and demagnetization of the superconducting coil.
[0013] According to a preferred embodiment, the current lead is fixed to the surface of the liquid nitrogen box by a copper clamp, and an insulating gasket is provided between the copper clamp and the liquid nitrogen box.
[0014] According to a preferred embodiment, the high-temperature superconducting magnet further includes a support member that extends through the nitrogen-fixing cavity and the cold screen, and respectively completes a fixed connection with the nitrogen-fixing cavity, the cold screen and the external Dewar.
[0015] According to a preferred embodiment, the support member has three mechanical interfaces at both ends, including a nitrogen-fixing chamber interface, a cold screen interface, and an external Dewar interface. The two ends of the support member are fixedly connected to the nitrogen-fixing chamber, the cold screen, and the external Dewar via the three mechanical interfaces.
[0016] According to a preferred embodiment, the cross-section of the main body of the support member is configured as a Z-shaped structure, and an insulating gasket is provided between the main body of the support member and the nitrogen fixation cavity.
[0017] According to a preferred embodiment, the cooling pipes on the inner side of the coil plate are integrally formed with the coil plate using metal 3D printing or superplastic diffusion welding.
[0018] According to a preferred embodiment, the coil box is integrally formed with the nitrogen-fixing cavity frame.
[0019] According to a preferred embodiment, the top of the nitrogen-fixing chamber is provided with a helium chamber, which is connected to the helium pipeline and the cooling pipeline on the inner side of the coil plate to complete the collection and distribution of helium gas flow.
[0020] The working process of the high-temperature superconducting magnet in this application can be as follows:
[0021] 1) Vacuum evacuation is performed on the external Dewar of the superconducting magnet through the vacuum evacuation port;
[0022] 2) Liquid nitrogen is introduced into the nitrogen-fixing chamber through the nitrogen-fixing chamber pipeline until all components in the nitrogen-fixing chamber are cooled to the temperature of liquid nitrogen and the nitrogen-fixing chamber is filled with liquid nitrogen;
[0023] 3) Inject liquid nitrogen into the liquid nitrogen box of the cold screen, and keep the liquid nitrogen boxes on both sides of the superconducting magnet full at all times;
[0024] 4) Connect the superconducting magnet to the external helium circulation system via a helium pipeline, and introduce low-temperature helium into the coil plate until nitrogen is fixed in the nitrogen fixation chamber;
[0025] 5) During the nitrogen fixation cooling process, replenish the nitrogen fixation chamber with liquid nitrogen until the nitrogen fixation chamber is filled with nitrogen medium, and keep the helium gas cooling until the temperature inside the nitrogen fixation chamber reaches a stable level;
[0026] 6) Connect the excitation power supply to excite the superconducting coil. Once the specified current is reached, the excitation is complete.
[0027] 7) Disconnect the excitation cable connected to the excitation power supply, and remove all cooling and vacuum pipelines to completely detach the superconducting magnet from the ground equipment.
[0028] The aforementioned main solution and its various further alternative solutions can be freely combined to form multiple solutions, all of which are solutions that can be adopted and are claimed in this application. Those skilled in the art, after understanding the solution of this application, will realize that there are many combinations based on the prior art and common general knowledge, all of which are technical solutions to be protected in this application, and will not be exhaustively listed here.
[0029] The beneficial effects of this application are:
[0030] The superconducting magnet of this application is applied to a magnetic levitation transportation system, which can achieve complete detachment of the cooling equipment, is easy to operate, and has a long offline operating time, reducing the weight of the levitation vehicle and increasing the upper limit of the operating speed.
[0031] The superconducting magnet involved in this application uses cryogenic helium for cooling, which has a lower cooling cost compared to liquid helium-cooled superconducting magnets, and a shorter cooling time and lighter weight compared to mechanically cooled magnets.
[0032] Compared to low-temperature superconducting magnets, the superconducting coils of the superconducting magnets involved in this application have higher mechanical strength and better vibration resistance, making them particularly suitable for the dynamic vibration environment of high-speed maglev transportation systems. Furthermore, compared to existing nitrogen-protected high-temperature superconducting magnets, the superconducting magnet of this invention has significantly higher structural strength than traditional single-coil-box structures because the coil box and nitrogen-fixed cavity frame are integrally formed. Attached Figure Description
[0033] Figure 1 This is a schematic diagram of the appearance of the superconducting magnet in this application;
[0034] Figure 2 This is a schematic diagram of the vacuum layer structure of a superconducting magnet;
[0035] Figure 3 This is a schematic diagram of the copper clamp structure;
[0036] Figure 4 This is a schematic diagram of the three-dimensional structure of the support component;
[0037] Figure 5 This is a schematic diagram of the cross-sectional structure of the support component;
[0038] Figure 6 This is a schematic diagram of the surface structure of the nitrogen-fixing cavity;
[0039] Figure 7 This is a schematic diagram of the coil board structure;
[0040] Figure 8 This is a schematic diagram of the internal structure of the nitrogen fixation chamber;
[0041] Among them, 1-external Dewar, 2-vacuum electrode, 3-cold shield pipeline, 4-signal aviation connector, 5-helium pipeline, 6-nitrogen fixation chamber pipeline, 7-cold shield, 8-liquid nitrogen box, 9-current lead, 10-support component, 11-copper clamp, 12-insulating gasket, 13-thermal insulation gasket, 14-nitrogen fixation chamber interface, 15-cold shield interface, 16-external Dewar interface, 17-nitrogen fixation chamber frame, 18-coil plate, 19-helium chamber, 20-superconducting coil, 21-superconducting switch, 22-coil box. Detailed Implementation
[0042] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. This application can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, unless otherwise specified, the following embodiments and features in the embodiments can be combined with each other.
[0043] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.
[0044] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this application is in use. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In addition, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.
[0045] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.
[0046] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.
[0047] Furthermore, it should be noted that unless otherwise specified in this application, the specific structures, connections, positions, power sources, etc. involved are all things that a person skilled in the art can know without creative effort based on the prior art.
[0048] Example 1
[0049] refer to Figures 1 to 8 As shown in the figure, a nitrogen-protected high-temperature superconducting magnet based on helium gas circulation cooling is illustrated. The high-temperature superconducting magnet includes an outer Dewar 1, a cold screen 7, and a nitrogen-fixing cavity. The nitrogen-fixing cavity is disposed within the cavity formed by the outer Dewar 1, and the cold screen 7 is disposed within the vacuum layer between the nitrogen-fixing cavity and the outer Dewar 1.
[0050] The nitrogen fixation chamber is composed of a nitrogen fixation chamber frame 17 and coil plates 18 located on both sides of the nitrogen fixation chamber frame 17. A coil box 22 is provided inside the nitrogen fixation chamber, and a superconducting coil 20 is provided inside the coil box 22.
[0051] The outer Dewar 1 is provided with a cold screen pipe 3 for providing a cooling medium to the cold screen 7; the outer Dewar 1 is also provided with a helium pipe 5 and a nitrogen-fixing chamber pipe 6. The helium pipe 5 is connected to the cooling pipe on the inner side of the coil plate 18 and is used to provide cooling helium to the nitrogen-fixing chamber. The nitrogen-fixing chamber pipe 6 is connected to the nitrogen-fixing chamber and is used to fill the nitrogen-fixing chamber with liquid nitrogen.
[0052] Preferably, the outer Dewar 1 is typically made of titanium alloy or stainless steel, which can withstand a negative pressure of 1 bar, providing outer shell protection and a vacuum environment for the internal structure of the magnet.
[0053] Preferably, the outer Dewar 1 is provided with a signal connector 4. The signal connector 4 is usually made of the same material as the outer Dewar 1 and is installed on the top of the outer Dewar 1 to enable the signal line to pass through the compartment. That is, the signal line can pass through the outer Dewar 1 without damaging the sealing performance of the outer Dewar 1, while ensuring that the signal line is insulated from the outer Dewar.
[0054] Preferably, the outer Dewar 1 is provided with a vacuum electrode 2, which consists of a copper lead core, a ceramic insulation structure and a stainless steel flange. This allows the current lead to pass through the outer Dewar without compromising its sealing performance, while simultaneously achieving insulation between the current lead and the outer Dewar.
[0055] Preferably, the material of the cold shield pipe 3 is usually aluminum alloy or stainless steel. This pipe is used to introduce liquid nitrogen into the cold shield system for cooling. A sleeve structure is installed on the outside of the pipe to prevent large-area frost from forming on the outer Dewar when liquid nitrogen is introduced. This pipe is installed with the ground cooling pipe using KF flanges, which can be quickly installed and removed.
[0056] Preferably, the helium pipeline 5 is typically made of stainless steel. This pipeline is used to introduce cryogenic helium into the magnet for cooling. A sleeve structure is installed on the outside of the pipeline to prevent large-area frost formation on the outer Dewar when cryogenic helium is introduced. This pipeline is connected to the ground cooling pipeline by screws, allowing for quick installation and removal.
[0057] Preferably, the nitrogen-fixing chamber pipeline 6 is typically made of titanium alloy or stainless steel. This pipeline is used to introduce liquid nitrogen into the nitrogen-fixing chamber for cooling. A sleeve structure is installed on the outside of the pipeline to prevent large-area frost formation on the outer Dewar when liquid nitrogen is introduced. This pipeline is installed with the ground cooling pipeline using a KF flange for quick installation and removal.
[0058] Preferably, the top of the cold screen 7 is provided with a liquid nitrogen box 8, which is connected to the cold screen pipeline 3 to receive liquid nitrogen; the liquid nitrogen box 8 conducts the cooling energy generated by the vaporization of liquid nitrogen to the cold screen 7, thereby cooling the cold screen 7.
[0059] Furthermore, a current lead 9 is fixed to the surface of the liquid nitrogen box 8, which is used to provide a power supply circuit for the excitation and demagnetization of the superconducting coil 20.
[0060] Furthermore, the current lead 9 is fixed to the surface of the liquid nitrogen box 8 by a copper clamp 11, and an insulating gasket 12 is provided between the copper clamp 11 and the liquid nitrogen box 8. The function of the copper clamp 11 is to utilize the low temperature of the liquid nitrogen box 8 to cool the vacuum layer current lead and prevent the current lead from overheating and burning during excitation or demagnetization.
[0061] Preferably, the cold shield 7 is typically made of aluminum alloy or copper, and its main function is to provide thermal radiation shielding for the internal nitrogen-fixing cavity structure while reducing heat conduction leakage from the support structure. The cold shield 7 is equipped with an assembly interface for the liquid nitrogen box 8, the support component 10, and the cold shield base plate.
[0062] Preferably, the liquid nitrogen box 8 is typically made of aluminum alloy or stainless steel and is used to store liquid nitrogen. The cooling energy generated by the vaporization of liquid nitrogen is transferred to the cooling screen 7, thereby cooling the cooling screen.
[0063] Preferably, the current lead 9 is made of copper and wrapped with an insulating material. Its function is to provide a power supply circuit for the excitation and demagnetization of the superconducting coil 20.
[0064] Preferably, the high-temperature superconducting magnet further includes a support member 10, which passes through the nitrogen-fixing cavity and the cold screen 7, and respectively completes the fixed connection with the nitrogen-fixing cavity, the cold screen 7 and the external Dewar 1.
[0065] Furthermore, the support member 10 is provided with three mechanical interfaces at both ends, including a nitrogen-fixing chamber interface 14, a cold screen interface 15, and an external Dewar interface 16. The two ends of the support member 10 are fixedly connected to the nitrogen-fixing chamber, the cold screen 7, and the external Dewar 1 via the three mechanical interfaces.
[0066] Preferably, the cross-section of the main body of the support member 10 is configured as a Z-shaped structure. This Z-shaped design enhances mechanical strength while extending the heat conduction path and reducing heat leakage. Furthermore, an insulating gasket 13 is provided between the support member 10 and the nitrogen-fixing cavity. The insulating gasket 13 is made of glass fiber composite material, further reducing heat leakage from the support member 10.
[0067] Preferably, the support member 10 is usually made of titanium alloy, stainless steel or glass fiber and carbon fiber composite material, as the main load-bearing structure of the superconducting magnet. The function of the support member 10 is to transfer the electromagnetic load on the superconducting coil to the room temperature confinement end.
[0068] Preferably, the nitrogen-fixing chamber is located at the center of the superconducting magnet and is used to prepare and store fixed nitrogen. It is the lowest temperature region in the superconducting magnet. The nitrogen-fixing chamber frame 17 and coil plate 18 are usually made of titanium alloy or stainless steel. When the ground cooling equipment is offline, the internal nitrogen-fixing heat capacity delays the temperature rise of the superconducting coil, thereby achieving offline cooling operation of the superconducting magnet.
[0069] Preferably, a cooling pipe is arranged on the inner side of the coil plate 18, and low-temperature helium gas can be introduced into the cooling pipe to cool the nitrogen medium inside the nitrogen-fixing chamber through indirect heat exchange. Furthermore, by using processes such as metal 3D printing or superplastic diffusion welding to integrally form the non-circular pipe with the coil plate 18, the heat exchange area can be increased, the cooling effect can be enhanced, and size and weight can be saved.
[0070] Preferably, the top of the nitrogen-fixing chamber is provided with a helium chamber 19, which is usually made of the same material as the coil plate 18. The helium chamber 19 is connected to the helium pipeline 5 and the cooling pipeline on the inner side of the coil plate 18 to complete the collection and distribution of helium gas flow.
[0071] Preferably, the coil box 22 is made of the same material as the nitrogen-fixing cavity frame 17, and houses the superconducting coil 20 inside. The superconducting coil 20 is fixed to the coil box by resin curing. The space between the outside of the coil box 22 and the inner wall of the nitrogen-fixing cavity can accommodate nitrogen fixation, providing a low-temperature environment for the superconducting coil 20. The coil box 22 can increase the mechanical strength of the superconducting coil 20 and prevent damage to the superconducting wire caused by the cold contraction stress generated during nitrogen fixation. In this superconducting magnet, the coil box 22 and the nitrogen-fixing cavity frame 17 are integrally formed, which can significantly improve the structural strength of the nitrogen-fixing cavity and the coil box, and is especially suitable for high-speed magnetic levitation systems.
[0072] Preferably, the nitrogen-fixing cavity is further provided with a superconducting switch 21, which is composed of a high-temperature superconducting tape, a glass fiber composite skeleton and an external heat insulation layer. A temperature sensor and a heating wire are embedded inside. The superconducting tape in the superconducting switch 21 can exhibit a superconducting state at low temperature and form a circuit with the superconducting coil 20 to realize the disconnection of the excitation power supply.
[0073] Preferably, the operating steps of the high-temperature superconducting magnet of this application include:
[0074] 1) Vacuum evacuation is performed on the superconducting magnet external Dewar 1 through the vacuum evacuation port;
[0075] 2) Pour liquid nitrogen into the nitrogen-fixing chamber until all components in the nitrogen-fixing chamber are cooled to the temperature of liquid nitrogen and the nitrogen-fixing chamber is filled with liquid nitrogen;
[0076] 3) Inject liquid nitrogen into the liquid nitrogen box 8 to keep the liquid nitrogen boxes 8 on both sides of the superconducting magnet always full;
[0077] 4) Connect the superconducting magnet to the external helium circulation system and introduce cryogenic helium into the coil plate until nitrogen is formed;
[0078] 5) During the nitrogen fixation cooling process, replenish the nitrogen fixation chamber with liquid nitrogen until the nitrogen fixation chamber is filled with nitrogen medium, and keep the helium gas cooling until the temperature inside the nitrogen fixation chamber reaches a stable level;
[0079] 6) The vacuum power supply of the external Dewar 1 of the superconducting magnet is connected to the excitation power supply to excite the superconducting coil 20. After the specified current is reached, the superconducting switch 21 is controlled to close the loop to complete the excitation.
[0080] 7) Disconnect the excitation cable, and remove all external cooling pipes and vacuum pipes. The superconducting magnet will be completely detached from the ground equipment, and magnetic levitation navigation can begin.
[0081] The superconducting magnet of this application is applied to a magnetic levitation transportation system, which can achieve complete detachment of the cooling equipment, is easy to operate, and has a long offline operating time, reducing the weight of the levitation vehicle and increasing the upper limit of the operating speed.
[0082] The superconducting magnet involved in this application uses cryogenic helium for cooling, which has a lower cooling cost compared to liquid helium-cooled superconducting magnets, and a shorter cooling time and lighter weight compared to mechanically cooled magnets.
[0083] Compared to low-temperature superconducting magnets, the superconducting coils of the superconducting magnets involved in this application have higher mechanical strength and better vibration resistance, making them particularly suitable for the dynamic vibration environment of high-speed maglev transportation systems. Furthermore, compared to existing nitrogen-protected high-temperature superconducting magnets, the superconducting magnet of this invention has significantly higher structural strength than traditional single-coil-box structures because the coil box and nitrogen-fixed cavity frame are integrally formed.
[0084] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.
Claims
1. A helium circulation refrigeration based nitrogen fixation shielded high temperature superconducting magnet, characterized by, The high-temperature superconducting magnet includes: an outer Dewar (1), a cold screen (7) and a nitrogen-fixing cavity. The nitrogen-fixing cavity is disposed within the cavity formed by the outer Dewar (1), and the cold screen (7) is disposed within the vacuum layer between the nitrogen-fixing cavity and the outer Dewar (1). The nitrogen fixation chamber is composed of a nitrogen fixation chamber frame (17) and coil plates (18) located on both sides of the nitrogen fixation chamber frame (17). A coil box (22) is provided inside the nitrogen fixation chamber, and a superconducting coil (20) is provided inside the coil box (22). The outer Dewar (1) is provided with a cold screen pipeline (3) for providing a cooling medium to the cold screen (7); the outer Dewar (1) is also provided with a helium pipeline (5) and a nitrogen-fixing chamber pipeline (6). The helium pipeline (5) is connected to the cooling pipeline on the inner side of the coil plate (18) for providing cooling helium to the nitrogen-fixing chamber. The nitrogen-fixing chamber pipeline (6) is connected to the nitrogen-fixing chamber for filling the nitrogen-fixing chamber with liquid nitrogen.
2. The nitrogen-fixed protected high-temperature superconducting magnet based on helium cycle cooling as described in claim 1, characterized in that, The top of the cold screen (7) is provided with a liquid nitrogen box (8), which is connected to the cold screen pipeline (3) to receive liquid nitrogen; the liquid nitrogen box (8) conducts the cooling energy generated by the vaporization of liquid nitrogen to the cold screen, thereby cooling the cold screen.
3. The nitrogen-fixed protected high-temperature superconducting magnet based on helium cycle cooling as described in claim 2, characterized in that, The liquid nitrogen box (8) has a current lead (9) fixed on its surface. The current lead (9) is used to provide a power supply circuit for the excitation and demagnetization of the superconducting coil (20).
4. The nitrogen-fixed protected high-temperature superconducting magnet based on helium cycle cooling as described in claim 3, characterized in that, The current lead (9) is fixed to the surface of the liquid nitrogen box (8) by a copper clamp (11), and an insulating gasket (12) is provided between the copper clamp (11) and the liquid nitrogen box (8).
5. The nitrogen-fixed protected high-temperature superconducting magnet based on helium cycle cooling as described in claim 1, characterized in that, The high-temperature superconducting magnet also includes a support member (10), which passes through the nitrogen fixation cavity and the cold screen (7) and is fixedly connected to the nitrogen fixation cavity, the cold screen (7) and the external Dewar (1) respectively.
6. The nitrogen-fixed protected high-temperature superconducting magnet based on helium cycle cooling as described in claim 5, characterized in that, The support member (10) has three mechanical interfaces at both ends, including a nitrogen-fixing chamber interface (14), a cold screen interface (15), and an external Dewar interface (16). The two ends of the support member (10) are fixedly connected to the nitrogen-fixing chamber, the cold screen (7), and the external Dewar (1) through the three mechanical interfaces.
7. The nitrogen-fixed protected high-temperature superconducting magnet based on helium cycle cooling as described in claim 5, characterized in that, The body section of the support member (10) is set as a Z-shaped structure, and an insulating gasket (13) is provided between the body of the support member (10) and the nitrogen fixation cavity.
8. The nitrogen-fixed protected high-temperature superconducting magnet based on helium cycle cooling as described in claim 1, characterized in that, The cooling pipes on the inner side of the coil plate (18) are integrally formed with the coil plate (18) by metal 3D printing or superplastic diffusion welding process.
9. The nitrogen-fixed protected high-temperature superconducting magnet based on helium cycle cooling as described in claim 1, characterized in that, The coil box (22) and the nitrogen-fixing cavity frame (17) are integrally formed.
10. The nitrogen-protected high-temperature superconducting magnet based on helium cycle cooling as described in claim 1, characterized in that, The nitrogen-fixing chamber is provided with a helium chamber at the top. The helium chamber is connected to the helium pipeline (5) and the cooling pipeline on the inner side of the coil plate (18) to complete the collection and distribution of helium gas flow.